Hybridization is a phenomenon in which single-stranded deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) molecules anneal to complementary DNA or RNA. Though a double-stranded DNA sequence is generally stable under physiological conditions, changing these conditions in the laboratory (generally by raising the surrounding temperature) will cause the molecules to separate into single strands. These strands are complementary to each other but may also be complementary to other sequences present in their surroundings. Lowering the surrounding temperature allows the single-stranded molecules to anneal or “hybridize” to each other.
Hybridization is useful in numerous molecular biology techniques including Southern blots and Northern blots, and most approaches to DNA sequencing. Overall, genetic relatedness of two species can be determined by hybridizing segments of their DNA (DNA-DNA hybridization). Due to sequence similarity between closely related organisms, higher temperatures are required to melt such DNA hybrids when compared to more distantly related organisms. A variety of different methods use hybridization to pinpoint the origin of a DNA sample, including polymerase chain reaction (PCR). In another technique, short DNA sequences are hybridized to cellular mRNAs to identify expressed genes. Researchers are also exploring the use of antisense RNA to bind to undesired mRNA, preventing the ribosome from translating the mRNA into protein.
Fluorescence in situ hybridization (FISH) is a technique that uses fluorescent probes that bind to only those parts of the chromosome with a high degree of sequence complementarity. It is used to detect and localize the presence or absence of specific DNA sequences on chromosomes. Fluorescence microscopy can be used to find out where the fluorescent probe is bound to the chromosomes. FISH is often used for finding specific features in DNA for use in genetic counseling, medicine, and species identification. FISH can also be used to detect and localize specific RNA targets (mRNA, lncRNA and miRNA) in cells, circulating tumor cells, and tissue samples. In this context, it can help define the spatial-temporal patterns of gene expression within cells and tissues.
In order to efficiently and effectively perform techniques such as FISH, robust experimental conditions are desired to provide reproducible and reliable results. Accordingly, there exists a need for reliable reaction media and conditions to perform these experiments.